Pilar sheath acanthoma

Pilar Sheath Acanthoma is a rare, benign cutaneous condition characterized by a solitary, firm, skin-colored papule that typically occurs on the face of elderly individuals. It was first described by Kint et al. in 1978.

Clinical Presentation

Pilar Sheath Acanthoma presents as a solitary, firm, skin-colored papule, usually less than 6 mm in diameter. It is most commonly found on the upper lip, but can also occur on the lower lip, nose, and other parts of the face. The lesion is typically asymptomatic, but can sometimes cause mild discomfort or cosmetic concern.

Pathogenesis

The exact pathogenesis of Pilar Sheath Acanthoma is unknown. It is believed to originate from the outer root sheath of the hair follicle, specifically the isthmus region. Some researchers suggest that it may be a hamartomatous process, while others propose that it could be a reactive or neoplastic process.

Diagnosis

The diagnosis of Pilar Sheath Acanthoma is primarily based on clinical examination and histopathological findings. The characteristic histological feature is a central invagination filled with keratinous material, surrounded by acanthotic epithelium that resembles the outer root sheath of the hair follicle.

Treatment

Treatment is not necessary unless the lesion causes discomfort or cosmetic concern. If treatment is desired, the most common method is surgical excision. Other treatment options include cryotherapy and laser ablation.

Prognosis

The prognosis for Pilar Sheath Acanthoma is excellent. It is a benign condition and does not have any malignant potential. However, recurrence can occur if the lesion is not completely excised.

See Also

• List of cutaneous conditions
• Hair follicle
• Acanthoma

References

• Kint A, Baran R, De Keyser H. Pilar sheath acanthoma. Dermatologica. 1978;157(4):238-244.
• Weedon D. Skin Pathology. 2nd ed. London: Churchill Livingstone; 2002.